Please help. I currently own a 97 F150 V6. I am having trouble with an low indication on the oil pressure gauge. I had it checked out and they can not find anything wrong with the oil pressure. The last two Saturdays I have used the truck to haul a pony in a smaller trailer to a local speed event show. While sitting at a light the oil pressure slowly goes down. If I put the truck into park it quickly recovers. I have had it checked out by a garage and they can not find anything wrong with the truck. Nancy

 

how many miles? what oil and filter? how many miles on the oil? i would guess the oil pressure sender is bad. or the bearings are shot.

 

Do you still have the stock oil pressure gauge & sending unit? If you do, the gauge should show no oil pressure, or read about half-scale. The stock oil pressure sending unit is a "normally open" switch, that closes with about 7PSI of oil pressure.

 

Thanks for the help, but don't know what you are talking about. I took the truck in to be checked and they couldn't find anything wrong with it. Last night when I was hauling my daughter and her pony to a game show it did it again. Now the oil pressure goes down when ever I take my foot off the accelerator. If I accelerate or put it in park it returns to normal. The truck has a factory installed tow package. The overdrive was turned off, but even if I turned it on it didn't make any difference. I don't know much about mechanical stuff, so you will need to inform on a very basic level. The truck has 113,000 miles on it. It get regular oil changes every 2500 miles. The oil level is not low. The gauge goes completely flat lined and the check oil light will turn on if I don't get moving or put it in park while sitting at a light. Thanks, Nancy

 

I was confused with your first post that the oil pressure gauge slowly goes down. It sounds like your oil pressure sending unit is bad.

 

I went to the auto shop and got a new oil pressure sensor. Its the thing that screws into the engine block. What size deep socket does it take to get the original one off. I have a deep socket wrench that fits the new one, but it seems the base on the original is bigger. Nancy

 

not sure what size. but you are on the right track. make sure its the right sender. the oil pressure sender is by the oil filter the water temp sensor is further up by the thermostat.

 

I found the place and the sensor, but unfortunately it appears to require a special deep socket to get it out. The replacement uses a standard wrench, but because Ford elected to make the base of the original so big it requires a wrench that just won't fit. I also found the water sensor you are talking about. That is on top of the motor.

Why do you think it only malfunctions when there is a load being hauled? Nancy

 

Hi
I Had The Same Thing In My 97 E150 With 54k.
Nobody Found The Problem. The Ford Dealer Told Me For Change The Engine. In Another Autoshop The Same Thing. The Engine Was Running Fine, But The Oil Pressure Was Flying Up And Down With The Speed Of The Engine.
I Spent 4600 Dolares In A New Jasper Remanufactured Engine.
This Engine Sucks With Long Bad Head Gaskets History.....

Good Luck

Clesio

 

I changed the oil pressure sending unit, and hooked up a trailer, loaded a pony and drove to the park with no oil pressure problems. If gas prices weren't so high, I would hook up again, and see if it still reads good. I am thinking that maybe the sending unit was bad. Not sure though. Only used the truck once since getting a new unit. Nancy

 

What kind of oil are you using? I have a 97 with the same problem. I live in orlando and drove down to Maimi, about half way I stopped at a light and the pressure gauge was jumping around. I was using 5w-20 at the time. Right now I'm using 10w-30. I think I will just replace the sender anyway, it shouldn't be very expensive. Have you had any problems since replacing it?

 

I have had no problems since replacing the sending unit, but I have only used the truck once to haul a pony to the park. The sending unit cost me 10.80 to purchase and another 30.00 to have installed. You need a special wrench to remove the factory installed one, but the one I purchased could be installed with the deep socket wrench. Nancy

 

Sounds good, I think I'll replace mine before I drive back to Massachusetts

 

That was the less expensive solution. Good luck and let me know how it goes. I am going to haul a couple of ponies to a speed show this weekend. I should know for sure if it fixed the problem. Nancy